1. Field of the Invention
The present invention relates generally to orthotic and prosthetic devices. In another aspect, the invention concerns a novel sheath system for facilitating the donning and wearing of a prosthesis on a residual limb by reducing the frictional forces between the residual limb and the prosthesis.
2. Description of the Prior Art
Every year, thousands of people undergo amputations. The predominant cause of amputation is peripheral vascular disease (PVD) and/or diabetes. Additional causes of amputation include trauma, congenital abnormalities, and other diseases such as cancer. In many cases amputees are elderly, have poor physical strength, and/or have fragile skin conditions. Thus, physical limitations may inhibit the ability of an amputee to adequately don a prosthesis. Additionally, shear or other forces within the socket of the prosthesis may lead to sores developing on fragile skin.
High frictional and compressional forces between the residual limb of an amputee and the prosthesis may pose many other problems and concerns. Friction within a prosthetic socket interface often increases proximal bunching of prosthetic socks, adductor rolls, proximally directed pressure of soft tissue, and xe2x80x9chammockingxe2x80x9d (i.e., lack of distal contact between the residual limb and the prosthesis) due to increased proximal tension from prosthetic sock piles. If these issues are not addressed adequately, the amputee""s functional abilities are often limited due to discomfort, fitting limitations, and/or the risk of developing sores on the residual limb. These risks are of great concern for amputees, especially those with conditions that may cause delayed healing, such as PVD or diabetes.
With some traumatic or congenital related amputations, the residual limb itself may present unique fitting considerations due to tissue consistency or irregular bone structure of the residual limb. Thus, the structure of the residual limb itself may cause difficulty in optimally fitting a prosthesis for ease of donning, comfort, and function.
It is an object of the present invention to provide a system for minimizing friction between a prosthesis and a residual limb, thereby facilitating the donning of a prosthesis on a residual limb and the removal of the prosthesis from the residual limb.
A further object of the invention is to provide an ultra low friction sheath having a configuration that allows it to be maintained in the socket of a prosthesis during use of the prosthesis, without causing discomfort to the wearer.
Another object of the invention is to provide a system for reducing proximal bunching of prosthetic socks, adductor rolls, proximally directed pressure of soft tissue, and xe2x80x9chammockingxe2x80x9d when a prosthesis is fitted on a residual limb.
Still another object of the invention is to provide a system for facilitating the donning of a prosthesis on a residual limb having an irregular shape or composition.
Yet another object of the invention is to provide a system for facilitating the donning of a shoe on a prosthetic foot.
It should be understood that the above-listed objects are only exemplary, and not all the objects listed above need be accomplished by the invention described and claimed herein.
Accordingly, in one embodiment of the present invention there is provided a low friction sheath for facilitating donning of a prosthesis on a residual limb. The sheath comprises an outer bag and an inner bag substantially received in the outer bag. The outer bag has an outer bag open end and an outer bag closed end, while the inner bag has an inner bag open end and an inner bag closed end. The inner and outer bags are joined to one another at their open ends, and the closed ends of the inner and outer bags have substantially similar rounded shapes.
In another embodiment of the present invention, there is provided a low friction sheath for facilitating donning and wearing of a prosthesis on a residual limb. The sheath comprises a first piece of low friction material, a second piece of low friction material, and a seam joining the first and second pieces of material. The first and second pieces of material have respective first and second rounded proximal ends, rounded distal ends, and circumscribing edges. The seam joins the first and second pieces of material at their circumscribing edges.
In a further embodiment of the present invention, there is provided a low friction sheath for facilitating donning and wearing of a prosthesis on a residual limb. The sheath comprises a hollow body formed primarily of a thin, pliable, low friction material. The body is generally elliptically shaped when in an unfolded position. The body presents first and second spaced-apart ends and a mid portion joining the ends. The body includes a preformed crease extending across the mid portion.
In a still further embodiment of the present invention, there is provided a method of donning a prosthesis on a residual limb and thereafter using the donned prosthesis. The method comprises the steps of: (a) placing a low friction sheath over at least a portion of the residual limb, wherein the sheath is formed primarily of a low friction material having a self coefficient of static friction of less than about 0.4; (b) inserting the sheath and the residual limb at least partly into a socket of a prosthesis; and (c) using the prosthesis for its intended purpose while the sheath is at least partly received in the socket of the prosthesis.
In a yet further embodiment of the present invention, there is provided a method of donning a shoe on a prosthetic foot comprising the steps of: (a) covering at least a portion of the prosthetic foot with a low friction prosthetic sheath; (b) inserting the sheath and the prosthetic foot at least partly into the shoe; and (c) using the shoe and prosthesis for their intended purposes while the sheath is at least partly received in the shoe.